When I purchased my car the previous owner had a Mercedes battery in it that had a vent line on it. Problem was the vent was draining onto the battery tray and corroding the tray and surrounding engine bay with battery acid. I removed the battery, the tray and neutralized the acid with baking soda. I had to buy color matched paint to redo the surrounding engine bay and painted the tray black. Reinstalled with a maintenance free battery, after that mess I wouldn't go any other way.